Wringer mops with replaceable cleaning sponges are well known and usually require the removal and replacement of a threaded bolt and nut to remove and replace the cleaning sponge. The removal and replacement of the threaded bolt and nut usually requires the use of hand tools which may not be readily available and which are not easily operable in the typical confined space available for positioning. Also, the nut and screw arrangement may become rusted or corroded with use and may be difficult to remove and replace.
U.S. Pat. No. 4,481,688 discloses a cleaning sponge connection that does not require bolts or screws. Essentially, an operating rod's latch hook is wedged into a sponge clamp's arcuate latch hook tunnel thereby holding the sponge clamp between a pair of opposing rollers. This design, however, suffers from three distinct disadvantages. First, changing the angular position of the cleaning sponge is awkward and difficult. The user must free the latch hook from its wedged position in the sponge clamp by forcing down one side of the sponge clamp, while keeping the rollers apart, and with enough longitudinal force to liberate the wedged latch hook. Second, the sponge mop relies on the rollers themselves to inhibit rotational movement of the cleaning sponge about the latch hook while in operation. This stress on the rollers has a deleterious effect on the rollers yieldable clamping, resulting in less force when squeezing water from the cleaning sponge. Third, the provided guide channel does not keep the sponge clamp properly oriented to the operating rod, the rollers, and the rest of the mop assembly, when removing or replacing the cleaning sponge.
Other prior art devices also present difficulties when removing and replacing the cleaning sponge. One known method of guiding a latch hook into position is to form an angled recess in the sponge clamp. One such prior art device, disclosed in U.S. Pat. No. 4,862,550, uses an offset downwardly sloped recess in combination with a raised tab in a sponge clamp's latch hook tunnel to guide the sponge mop's latch hook into the sponge clamp. The latch hook is then pivoted into alignment with the longitudinal center line of the retaining latch hook tunnel. Initial and final alignment, however, rely on the installer's ability to orchestrate the operating rod, the sponge clamp, and the opposing rollers in parallel and angled positions in tight spaces. In addition, this sponge clamp relies on the opposing rollers to inhibit rotational movement about the latch hook.
Still other prior art devices are designed as multipurpose replacement sponge assemblies for mops. U.S. Pat. No. 4,908,901, for example, is designed for use with a variety of different mops. A first connection is provided by a threaded screw at the top of a latch hook tunnel so that an operating rod can be threaded therethrough. Although a threaded screw attachment does inhibit rotational movement, the threads may be stripped or otherwise corroded. A second connection means is provided by two raised tabs, each of which receive a spaced apart L-shaped connecting element. Both the tabs and the L-shaped connecting elements suffer from a necessarily light construction to facilitate their placement. This designed flexibility lends itself to fatigue, brittleness, and failure. A third connection means accepts an operating rod's latch hook. The attachment means for a latch hook, however, fails to inhibit rotational movement about the latch hook and does not provide an orienting guide means.